British scientists have developed a rooftop vegetation recycling system that allows water to be used twice before being discarded.
The Green Roof Water Recycling System uses semi-aquatic plants to treat waste washing water, which can then be reused for activities such as flushing toilets.
The device is the brainchild of Chris Shirley-Smith, whose company, Water Works UK, is collaborating with Imperial College London and Cranfield University.
So-called grey water from washbasins, baths and showers is pumped up to the rooftop system, which consists of an inclined framework of interconnected horizontal troughs. Planted in the troughs are specially chosen plants.
Dissolved pollutants in the water are taken up by the plants' roots, leaving "green water," or non-drinkable water. The scientists say such water can then be dyed with a vegetable color to signal its non-potable status, or it can be used to flush toilets or water a garden.
The researchers note more than half the water used in homes and workplace does not need to be potable, yet it comes from the same water source that feeds kitchen faucets.
The researchers hope to market their invention commercially during the second half of 2006.
Copyright 2005 by United Press International
Explore further: Earth's 'technosphere' now weighs 30 trillion tons, research finds